Résumé
Assessment the efficiency of separating zygomaticmaxillary buttresses, with or without midpalatal suture osteotomy, on shape and size expansion of the maxilla using palatal distractor. Fourteen adult patients [ages between 18-25 years and no inborn deformities or congenital syndromes] with skeletal maxillary narrowness being clinically and radially assessed. The studied sample is separated to two groups; Group I: seven patients with bilateral zygomaticmaxillary buttress osteotomy, Group II: the previous procedure was repeated on another 7 patients but with midpalatal osteotomy. The expansion in group II has V shape vertically and horizontally, but that was not clear in group I [p=0.03]. Also the maxillary width immediately and 6 months after the expansion in group II increased statistically when compared with group I [p=0.00], and the percentage of skeletal maxillary expansion after 6 months in group I was 26.17%, but it was 61.88% in group II. We conclude that midpalatal osteotomy affects the shape of expansion and increases the percentage of skeletal maxillary expansion in adults